The ballast of the railway track is constantly changing due to dynamic forces of train traffic that results in the crushing of the rocks. The feasibility to simulate each particle makes the discrete element method (DEM) suitable for the task. Different DEM particle models are introduced in our paper and the adequate one was chosen. This new method is based on crushable convex polyhedral element...

A 65 year old woman with gall stones presented with crushing chest pain after an attack of biliary colic. The electrocardiogram showed ST segment elevation in leads I, aVL, and V1-V3 while leads II, III, and aVF showed ST segment depression. Cardiac enzyme activity remained within the normal range. During the next three weeks attacks of epigastric and right hypochondrial pain preceded by crushi...

pulse oximetry measures the relative concentration of arterial oxygenated hemoglobin and reduced hemoglobin. this paper presents the design of a pulse oximeter, which measures the presence of a third substance, carboxyhemoglobin (hbco), by unfiltered leds at 660 nm, 810 nm, and 940 nm. background information is given on the theory of pulse oximetry. theoretical approximations and calculations w...

Inducible defences are widely used for studying phenotypic plasticity, yet frequently we know little about the cues that induce these defences. For aquatic prey, defences are induced by chemical cues from predators (kairomones) and injured prey (alarm cues). Rarely has anyone determined the separate and combined effects of these cues, particularly across phylogenetically diverse prey types. We ...

There has been a terrifying ‘logic’ to the protracted civil war in Sri Lanka which came to its very sad conclusion in the third week of May 2009. It is easy to understand why people living in Colombo and the south-western part of Sri Lanka felt very relieved and even enthused by the brutal crushing of the Tamil Tiger after twenty-six years of insecurity and conflict. However, any sense of victo...

Stainless steel square honeycomb core sandwich and solid monolithic beams have been subjected to high-pressure, short-duration impulses using a shock simulation technique involving high-speed impact of Al foam projectiles. The experiments have been designed to achieve two objectives: (i) to demonstrate the benefits of sandwich construction, and (ii) to assess the fidelity of dynamic finite elem...

In this paper, the discrete element method is used to explore why differing amounts of breakage, quantified using Hardin’s relative breakage parameter (Br), are associated with the critical state line (CSL) and the normal compression line (NCL) at similar stress levels. Virtual samples initially containing more than 20,000 spherical particles were isotropically compressed to a range of confinin...